You and Draco were talking quietly in the astronomy tower, he was squatting on the floor, and you were standing, he was flirting with you supposedly as a joke, so you answered him

"Sorry, Malfoy, but I don't like short guys" you said in a jokingly flirtatious tone

Draco laughed, and he stood up, and you saw how tall he was

"Now, do you like it?"